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| Identifiers | |
|---|---|
3D model (JSmol) | |
| ChemSpider | |
| UNII | |
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| Properties | |
| N2Na2O3 | |
| Molar mass | 121.991 g·mol−1 |
| Appearance | white solid |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Angeli's salt,sodium trioxodinitrate, is theinorganic compound with the formula Na2[N2O3]. It contains nitrogen in an unusual reduced state. It is a colorless, water-soluble solid, hence a salt. In research, this salt is used as a source of the metastablenitroxyl (HNO), which is a signalling molecule in nature.[1] It is also known by the namesodium trioxodinitrate(II) monohydrate.
As first reported byAngelo Angeli in 1896, the salt is prepared by combining hydroxylamine and an organic nitrate, as a source ofnitronium (NO+
2):[2][3]
The structure of the hydrate has been confirmed byX-ray crystallography. The anion is planar. Starting from the ONN end, the bond distances are 1.35 Å (N–O), 1.26 Å (N–N), 1.31 Å (N–Otrans), and 1.32 Å (N–Ocis). The negative charge is on the oxygen atoms at opposite ends of the molecule. The angles are 112.9° (Osingle–N–N), 118.4° (N–N–Otrans), and 122.5° (N–N–Ocis). This means that the nitrogen–nitrogen bond is adouble bond, and that thecis oxygen is slightly repelled by the single oxygen.[4]
Reaction of Angeli's salt withsecondary amines in the presence of a proton source results in extrusion of N2 viaisodiazenes as proposed intermediates.[5]
